1. Field of the Invention
The present invention relates to an image processing method and an image processing apparatus. More particularly, it relates to an image processing method and an image processing apparatus, in which a color conversion table utilized for color conversion processing of an image input device such as, for example, a scanner and a digital still camera (hereinafter, simply referred to as camera), is generated and color conversion processing is performed using the color conversion table.
2. Description of the Related Art
A method by which a user performs favorite color conversion on an input image obtained from a scanner or a camera is disclosed in Japanese Patent Laid-Open No. 2002-077659. In Japanese Patent Laid-Open No. 2002-077659, a method by which a user performs color adjustment of a sample image while watching a display device, and performs favorite color conversion by generating a multi-dimensional color conversion table based on the result of the color adjustment, is proposed. In other words, Japanese Patent Application Laid-Open No. 2002-077659, discloses that, in an image color adjustment processing section, a three-dimensional LUT is generated in response to the color adjustment performed by the user, and the image color conversion processing section performs color conversion processing favored by the user, based on the three-dimensional LUT.
As for a camera, conventionally, many data in sRGB (hereinafter referred to as a standard color space) has been treated, however, in recent years, not only the data in the standard color space but also many data in Adobe RGB, Wide Gamut RGB or the like (hereinafter referred to as an expanded color space) has come to be treated. However, in many conventional methods, not the data in the expanded color space, but the data in the standard color space is used as an object of color conversion, and the object corresponds to a single color space.
Specifically, in a conventional method such as Japanese Patent Laid-Open No. 2002-077659, color adjustment of a sample image is performed while watching a display device, and a color conversion table is generated based on the data of color adjustment, but most of the display devices generally used treat the data in the standard color space. Therefore, when a favorite color conversion is performed on the data in the expanded color space, since the result can not be correctly displayed on the display device, it is difficult to perform color adjustment intended by a user. In addition, it is also difficult to generate a color conversion table responding to the expanded color space.
Moreover, in the conventional method, only an image of the same color space as that of the image used for performing color adjustment is caused to be an object of color conversion. Also in Japanese Patent Laid-Open No. 2002-077659, the image color conversion processing section also performs color conversion by directly using a three dimensional LUT generated by the image color adjustment processing section. In other words, even if the color conversion table generated using the image in the standard color space is tried to be applied to the image of an expanded color space, since it does not respond to colors outside the color gamut of the standard color space, it is difficult to perform color conversion on colors outside the standard color space.
As mentioned above, in a conventional method, there is a problem in that when the color space of a sample image is different from that of the display device, it is difficult to perform color adjustment while watching the display device. Moreover, there is also a problem in that, the method cannot handle a case in which the color space of the image color adjustment processing section for performing color adjustment of an image and the color space of the image color conversion processing section for performing color conversion of the image are different from each other.
Moreover, along with the advance of a recent image processing technology and a printing technology, there is a demand to perform displaying on a display or printing in a color space with a color gamut widened in response to the desire of a user. In other words, it is desired that color conversion can be performed not only in a first color space (for example, a standard color space), but also in a second color space (an expanded color space) different from the first color space.